The document 100-HQ-3-116 Serial 253X contains the infamous passage in which William Sullivan, responding to criticism from J. Edgar Hoover, describes Martin Luther King Jr. in these terms after his speech at the March on Washington: "we must mark him now, if we have not done so before, as the most dangerous Negro of the future in this Nation from the standpoint of communism, the Negro and national security."

Document 100-HQ-3-116 Serial 684 describes a meeting by FBI leaders to develop ways of "neutralizing King as an effective Negro leader and developing evidence concerning King’s continued dependence on communists for guidance and direction."

A "not recorded" serial from 100-HQ-3-116, dated January 8 1964, discusses how, if the revelations of King's extra-marital affairs are "handled properly", it will be possible to "take him [King] off his pedestal and to reduce him completely in influence so that he will no longer be a security problem and will no longer be deceiving and misleading the Negro people." The rest of the document then speculates about ways the FBI could help replace King with "the right kind of a national Negro leader", and considers Samuel Pierce as a possible candidate. 

Also included are two documents from the FBI's main Headquarters file on its counterintelligence program (COINTELPRO) against what it first called "black hate", and later called "black extremism." 

The first (Aug. 25, 1967) explains the program's purpose, which is "to expose, disrupt, misdirect, discredit or otherwise neutralize the activities of black nationalist, hate-type organizations and groupings, their leadership, spokesmen, membership and supporters, and to counter their propensity for violence and civil disorder", and lists King's Southern Christian Leadership Conference (SCLC) one of its targets. 

The second (March 4, 1968) describes one of the "goals" of the program as being to "Prevent the rise of a 'messiah' who could unify, and electrify, the black nationalist movement. Malcolm X might have been such a 'messiah;' he is the martyr of the movement today. Martin Luther King, Stokely Carmichael, and Elijah Muhammad all aspire to this position."